Highly repeated nuclear DNA sequences from suspension cultured cells of Oryza sativa L. cv. 'Roncarolo' have been cloned in pBR322. Ten clones with specific digestion patterns have been randomly selected. Nine sequences appear to be organized in a clustered tandem array while one is interpersed in the rice genome. The clones have been used to gather information on: (a) their modulation in cultured cells as compared to whole plant and (b) their distribution in different rice cultivars belonging to the Japonica or Indica subspecies of Oryza sativa L. Hybridization with nuclear DNA isolated either from suspension or from seedlings of the 'Roncarolo' cultivar revealed extensive quantitative variations, with most cloned sequences showing amplification (up to 75-fold) in cultured cells. Hybridization with nuclear DNA isolated from seedlings or suspension cultured cells from different cultivars belonging to the Japonica or to the Indica sub-species of O. sativa have shown that (a) amplification also occurs in a similar pattern in the case of DNA from the other tested suspension cultured cell types but not in the case of DNA from seedlings; (b) in some cases the tested sequences show minor but significant variations in different rice accessions.

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Dahlia pinnata Cavanilles 1791 is an important ornamental plant worldwide. The chloroplast genome has obvious advantages in studies of systematic evolution at the plant classification and species level, making it an important resource for phylogenetic research.Here, we sequenced the full chloroplast genome from D. pinnata 'Chocolate' and found that it exhibited a typical tetrad structure. The full-length D. pinnata chloroplast genome was 152,107 bp, with a GC content of 38.45%. The genome included an 83,704 bp large single-copy (LSC) region, an 18,347 bp small single-copy (SSC) region, and a pair of 25,028 bp inverted repeats (IRa and IRb). A total of 134 genes were annotated, including 86 protein-coding genes, 38 transfer RNA genes, 8 ribosomal RNA genes, and 2 pseudogenes. Analysis of password preferences shows that passwords chosen by D. pinnata tend to end with A/U. A total of 161 SSR markers were detected in the simple sequence repeat (SSR) analysis. Phylogenetic analysis that the Dahlia species formed a monophyly. Dahlia was clustered with Cosmos-Bidens, which differed from studies using nuclear genomic DNA. We suggest that nuclear-cytoplasmic incongruences may be widespread in Asteraceae, and should be thoroughly evaluated in order to understand the true evolutionary history of this economically-important group of plants.

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